scholarly journals On Continuity of Evolution of Amino Acids

2019 ◽  
Vol 8 (3) ◽  
pp. 3071-3076
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Crucial Role ◽  
Evolutionary Biology ◽  
Continuous Evolution ◽  
Phenotype Space

Continuity plays a crucial role in any discussion on evolution. A nearness relation in the phenotype space allows to distinguish continuous evolution from discontinuous one. The genotype-phenotype map plays a crucial role in evolutionary biology. In this paper we have investigated continuity in evolution of amino acids. Nearness relations in the space of amino acids as well as in the set of codons are introduced. Here any codon is a genotype and the corresponding amino acid is the phenotype. We examined the continuity of the genotype-phenotype map with respect different neighbourhood structures of amino acids.

scholarly journals Continuity in Evolution from Codons to Amino Acids

2019 ◽  
Vol 8 (12) ◽  
pp. 3190-3193
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Crucial Role ◽  
Evolutionary Biology ◽  
Continuous Evolution ◽  
Phenotype Space

Continuity plays a crucial role in any discussion on evolution. The genotype-phenotype map focus crucial role in evolutionary biology. A nearness relation in the phenotype space allows distinguishing continuous evolution from discontinuous one. In this paper we have investigated continuity in evolution of amino acids. Uniform structures in the space of amino acids as well as in the set of codons are introduced. Here any codon is a genotype and the corresponding amino acid is the phenotype. We examined the continuity of the genotype-phenotype map with respect different uniform structures of codons.

The origin of translation and the genetic code

1997 ◽  
Author(s):  
John Maynard Smith ◽  
Eors Szathmary
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Genetic Code ◽  
Evolutionary Biology ◽  
Stop Codon ◽  
Rna World ◽  
Complex Function ◽  
Translational Machinery ◽  
Origin Of Translation ◽  
Specific Association

The origin of the code is perhaps the most perplexing problem in evolutionary biology. The existing translational machinery is at the same time so complex, so universal, and so essential that it is hard to see how it could have come into existence, or how life could have existed without it. The discovery of ribozymes has made it easier to imagine an answer to the second of these questions, but the transformation of an ‘RNA world’ into one in which catalysis is performed by proteins, and nucleic acids specialize in the transmission of information, remains a formidable problem. We start, in section 6.1, by discussing changes known to have occurred in the code since its origin. Although these changes are minor, they do shed some light on how the code may have evolved in its very early days. In section 6.2, we ask what can be deduced from the present assignment of codons to amino acids, and from the phytogeny of tRNAs. Finally, in section 6.3, we come to grips with the hardest question: how did a specific association between particular amino acids and particular codons first come into existence? It is this association that is the essence of the code. Today, it plays a role in translation, but we think it first arose to serve quite a different function. If so, this is an example of a common feature of evolution: structures that today serve a complex function arose first to serve a simpler one. For many years the common genetic code was thought to be universal. Recently, some interesting exceptions have been found. These are of two types: either a stop codon is used to code for an amino acid, or a codon has been reassigned to a different amino acid. At first sight it is hard to see how this could happen. To alter the meaning of a codon in one particular gene might be a selective advantage, just as any mutation might be, but to alter its meaning wherever it occurs throughout the genome must surely be disastrous.

Can the topological distribution of membrane spanning amino acid residues be responsible for the recognition of signal peptides by signal peptide peptidases?

1990 ◽  
Vol 10 (6) ◽  
pp. 537-546
Author(s):  
Ujwal P. Shinde
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Signal Peptide ◽  
Crucial Role ◽  
Alpha Helix ◽  
Signal Peptides ◽  
Amino Acid Residues ◽  
Selective Degradation ◽  
Membrane Spanning ◽  
Hydrolysis Of

Signal peptides are selectively recognized and degraded by membrane associated proteases called as signal peptide peptidases. The hydrolysis of the signal peptide occurs only after its cleavage from the precursor. The possible reasons for this selectivity have been investigated. The results indicate that in signal peptides, leucine residues are clustered to a large extent on the same side of the membrane spanning alpha helix as the polar residues, but are distinctly separated along the length of the axis. Such topological differences in the distribution of amino acids on the surface of the membrane spanning alpha helix may play a crucial role in selective degradation of signal peptides.

Dietary intake of tryptophan tied emotion-related impulsivity in humans

2019 ◽  
pp. 1-8 ◽  
Author(s):  
Florian Javelle ◽  
Descartes Li ◽  
Philipp Zimmer ◽  
Sheri L. Johnson
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Food Intake ◽  
Essential Amino Acid ◽  
Food Habits ◽  
Psychological Disorder ◽  
Serotonin Synthesis ◽  
Amino Acid Tryptophan ◽  
Pass Through ◽  
Three Factor

Abstract. Emotion-related impulsivity, defined as the tendency to say or do things that one later regret during periods of heightened emotion, has been tied to a broad range of psychopathologies. Previous work has suggested that emotion-related impulsivity is tied to an impaired function of the serotonergic system. Central serotonin synthesis relies on the intake of the essential amino acid, tryptophan and its ability to pass through the blood brain barrier. Objective: The aim of this study was to determine the association between emotion-related impulsivity and tryptophan intake. Methods: Undergraduate participants (N = 25, 16 women, 9 men) completed a self-rated measure of impulsivity (Three Factor Impulsivity Index, TFI) and daily logs of their food intake and exercise. These data were coded using the software NutriNote to evaluate intakes of tryptophan, large neutral amino acids, vitamins B6/B12, and exercise. Results: Correlational analyses indicated that higher tryptophan intake was associated with significantly lower scores on two out of three subscales of the TFI, Pervasive Influence of Feelings scores r =  –.502, p < . 010, and (lack-of) Follow-Through scores, r =  –.407, p < . 050. Conclusion: Findings provide further evidence that emotion-related impulsivity is correlated to serotonergic indices, even when considering only food habits. It also suggests the need for more research on whether tryptophan supplements might be beneficial for impulsive persons suffering from a psychological disorder.

Purification of Antihemophilic Factor (Factor VIII) by Amino Acid Precipitation*

1964 ◽  
Vol 11 (01) ◽  
pp. 064-074 ◽  
Author(s):  
Robert H Wagner ◽  
William D McLester ◽  
Marion Smith ◽  
K. M Brinkhous
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Factor Viii ◽  
Plasma Protein ◽  
Acid Precipitation ◽  
Aminobutyric Acid ◽  
Gamma Aminobutyric Acid ◽  
Specific Procedure ◽  
Beta Alanine ◽  
Antihemophilic Factor

Summary1. The use of several amino acids, glycine, alpha-aminobutyric acid, alanine, beta-alanine, and gamma-aminobutyric acid, as plasma protein precipitants is described.2. A specific procedure is detailed for the preparation of canine antihemophilic factor (AHF, Factor VIII) in which glycine, beta-alanine, and gammaaminobutyric acid serve as the protein precipitants.3. Preliminary results are reported for the precipitation of bovine and human AHF with amino acids.

Complete Covalent Structure of Human Platelet Factor 4

1979 ◽  
Vol 42 (05) ◽  
pp. 1652-1660 ◽  
Author(s):  
Francis J Morgan ◽  
Geoffrey S Begg ◽  
Colin N Chesterman
Keyword(s):  
Amino Acids ◽  
Molecular Weight ◽  
Amino Acid ◽  
Amino Acid Sequence ◽  
Human Platelet ◽  
Platelet Factor 4 ◽  
Platelet Factor ◽  
Disulphide Bonds ◽  
Covalent Structure

SummaryThe amino acid sequence of the subunit of human platelet factor 4 has been determined. Human platelet factor 4 consists of identical subunits containing 70 amino acids, each with a molecular weight of 7,756. The molecule contains no methionine, phenylalanine or tryptophan. The proposed amino acid sequence of PF4 is: Glu-Ala-Glu-Glu-Asp-Gly-Asp-Leu-Gln-Cys-Leu-Cys-Val-Lys-Thr-Thr-Ser- Gln-Val-Arg-Pro-Arg-His-Ile-Thr-Ser-Leu-Glu-Val-Ile-Lys-Ala-Gly-Pro-His-Cys-Pro-Thr-Ala-Gin- Leu-Ile-Ala-Thr-Leu-Lys-Asn-Gly-Arg-Lys-Ile-Cys-Leu-Asp-Leu-Gln-Ala-Pro-Leu-Tyr-Lys-Lys- Ile-Ile-Lys-Lys-Leu-Leu-Glu-Ser. From consideration of the homology with p-thromboglobulin, disulphide bonds between residues 10 and 36 and between residues 12 and 52 can be inferred.

Single Amino Acid Based Self-Assemblies of Cysteine and Methionine

2018 ◽  
Author(s):  
Nidhi Gour ◽  
Bharti Koshti ◽  
Chandra Kanth P. ◽  
Dhruvi Shah ◽  
Vivek Shinh Kshatriya ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Self Assembly ◽  
Aromatic Amino Acids ◽  
Neutral Condition ◽  
Single Amino Acid ◽  
Binding Assays ◽  
Human Neuroblastoma ◽  
Cytotoxicity Assays ◽  
First Time

We report for the very first time self-assembly of Cysteine and Methionine to discrenible strucutres under neutral condition. To get insights into the structure formation, thioflavin T and Congo red binding assays were done which revealed that aggregates may not have amyloid like characteristics. The nature of interactions which lead to such self-assemblies was purported by coincubating assemblies in urea and mercaptoethanol. Further interaction of aggregates with short amyloidogenic dipeptide diphenylalanine (FF) was assessed. While cysteine aggregates completely disrupted FF fibres, methionine albeit triggered fibrillation. The cytotoxicity assays of cysteine and methionine structures were performed on Human Neuroblastoma IMR-32 cells which suggested that aggregates are not cytotoxic in nature and thus, may not have amyloid like etiology. The results presented in the manuscript are striking, since to the best of our knowledge,this is the first report which demonstrates that even non-aromatic amino acids (cysteine and methionine) can undergo spontaneous self-assembly to form ordered aggregates.

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